On a regional basis emissions of windblown dust can degrade air quality below accepted limits and under extreme storm conditions can result in loss of human and animal life as well as severe environmental degradation. The delivery of dust-sized particles (<70 μm) to the atmosphere is an aerodynamically-driven process. There is complex interplay, however, between the resisting and driving forces that control the release and entrainment of these particles and the vertical flux of dust. Entrainment of dust into the wind occurs principally when sand-sized particles transported by the wind (saltation) impact the surface and eject dust sized particles. Dust can also be released to the airflow as aggregates of sediment break down during the vigorous transport process.